Re: seeing light flashes

["David W. Palmer" <dpalmer@post.its.mcw.edu>]

I worked somewhat with C.A. Tobias's Lawrence Berkeley Group in the early 
seventies and noted that several investigators were putting their eyes  
into the beams of energetic heavy ions.  This work was motivated by 
reports that the astronauts were seeing flashes.  A quick search of 
Tobias in the 70's on MedLine revealed three publications that might be 
of interest:
   1.  Visual Perception of accelerated nitrogen nuclei interacting with 
the human retina, by Budinger TF, Lyman JT and Tobias CA, in Nature, vol 
239, pp 209-211, 1972.
   2.  Radiation-induced light flashes observed by human subjects in fast 
neutron, x-ray and positive pion beams, by Tobias, Budinger and Lyman, in 
Nature, vol 230,  pp596-598, 1971.
   3.  Visual phenomena noted by human subjects on exposure to neutrons 
of energies less than 25 million electron volts, by Budinger, Bichsel H, 
and Tobias, in Science, vol 172, pp 868-870, 1971.

I also found in my files a copy of Science News, Oct 16, 1971 on the 
front cover of which was pictured Budinger and Tobias watching Edwin M. 
McMillan, director or LBL, as he put his head into the heavy-ion beam 
from the Bevatron. The accompanying article was titled "Accelerating 
heavy ions in the Bevatron. Author is Dietrick E. Thomsen.

It seems to reject as a cause of the flashes Cerenkov light emitted as 
the ions passed through the vitreous humor of the eye since the carefully 
collimated beam had to pass through the retina for the flashes to be 
seen. I will be glad to FAX anyone wishing a copy.

David W. Palmer
DPALMER@Post.ITS.MCW.edu